Yes! Had this happen last year! I never caught the culprit but the possibilities were: chipmunk, squirrel, bunny or groundhog/woodchuck.

I actually just went outside and found that the culprit was some sort of larvae, most likely a moth caterpillar. I actually was poking around my garden on Friday night, as I had gotten home late, and saw one near another small group. I thought nothing of it and saw the next day that the few crocuses he got to were chewed almost to the ground. I'm looking online for an Id and am hoping he was the only one, I'll keep an eye out for others.

Oh, interesting. Mine were definitely a rodent because every single crocus looked like that and I saw no insect activity. I wonder if winter moth likes crocus?

It definitely wasn't a winter moth caterpillar, still not sure what it was. I should've gotten a picture...

Not for this case, but as a heads up for lovers of yellow crocus: sparrows love to peck those to pieces. My mom told me long ago in Holland, here in Canada I have seen the same thing. Purples seem to be safe from them.

I blame the rabbits for mine. Also the tulip foliage

Hungry hippos?

gdinie, around here the yellow crocus get shredded by the American Gold Finches. I've seen them in the act.

.....But only the flowers, never bothering the foliage, like is the OP's problem.